This invention relates to a pollution control device and method; and more particularly to a device and method, which render the pollution caused by hydrocarbons harmless by using a combination of burning a hydrocarbon-containing exhaust under appropriate turbulent conditions and catalytically treating the burned hydrocarbons.
As a result of modern society and its manufacturing processes, an number of pollutants are produced, which pollutants can have an adverse effect on the environment. Yet, these processes are a necessary part of modern society. On the other hand, these same processes may cause pollution. It is always desirable to balance the advantages to society against the pollution caused by various industrial processes.
Certain industrial processes can produce noxious, odorous materials in gaseous form. These materials act as poisons, which are damaging to the environment and to the people close to the place where the processes are being practiced. This environmental damage is under increasing scrutiny from the Federal and State Environmental Protection Agencies. The basic problem is to maintain the advantages of these systems which produce the harmful materials, while materials.
Noxious gases and vapors produced by these products must be changed to harmless substances. A variety of processes are available to handle this problem of converting the harmful pollutants to the harmless compositions. Most of these devices for carrying out these conversion processes tend to be costly. Those devices which are not costly tend to be ineffective. The costliness is a result of the expense of putting together the system to remove the noxious substance and of the expense of maintaining the system.
Furthermore, it is highly critical that, whatever device or method is used to remove these noxious substances from the air, the device or method must be efficient, and not damage or substantially interfere with the manufacturing process. For example, if the device is too heavy to be simply supported by the manufacturing system, a tremendous amount of restructuring and costly supports are required.
These problems are especially difficult with regard to printing processes. These printing processes are useful. However, high speed printing processes common today use hydrocarbon oils or liquids as carriers for the pigment of the printing ink. These hydrocarbon oils permit very high speed printing processes, but give off pollution-causing, harmful vapors or gases. These harmful gases are in the form of hydrocarbon emissions from the heat set, web, offset inks and other processes. Of course, such materials are of great concern to those interested in preventing or minimizing pollution.
It is possible to burn the hydrocarbon oil vapors. However, the temperature required is in excess of 900.degree. Centrigrade (1,500.degree. Fahrenheit). The expense of such a system is too high in terms of fuel alone. The difficulty of constructing a system capable of handling such high temperatures adds to the complicated aspects of maintaining manufacturing efficiency, while minimizing pollution. Thus, burning along is an impractical method of pollution control.
California has especially stringent pollution controls. No nuisance odors are permitted. Generally, California requires ninety (90%) percent removal of hydrocarbons, zero (0) opacity and odor removal. These restrictions are very tough to meet.
Catalytic conversion of pollutants is also an impractical method of controlling pollution. Catalysts are usually made of noble metals and are, therefore, expensive. The catalysts also must be replaced on a regular basis. Thus, catalysts alone are an impractical method of pollution control.
Attempts to combine catalytic treatment with burning have proven difficult. If the burner assembly is highly efficient and runs at a temperature high enough to burn most of the pollutants, the flame contacts the expensive catalyst and shortens the useful life thereof. If the burner temperature is too low, the catalyst must receive too much of the pollution material and have a shorter life.
Success in removing hydrocarbons from exhausts of processes is measured in certain ways. One such way is determined from the opacity of the treated exhaust. The more opaque the exhaust from the pollution control system is, the less efficient the system is. Thus, if visible emissions are reduced, a substantial advantage is obtained.
It is also desirable to remove at least eighty five (85%) percent of the hydrocarbons from a pollution exhaust containing the same. It is also desirable to reduce odor in the system. The factors make pollution control in these fields very difficult.
It is, therefore, clearly desirable to develop an apparatus and a method for reducing and minimizing the environmental impact of these harmful materials which in a cost efficient manner with minimal interference with the manufacturing process.